1. Technical Field of the Invention
This invention relates to ultraviolet light stabilizing sterically hindered polyoxyalkylene polyamines. In another aspect this invention relates to ultraviolet light stabilizing; oxidation inhibiting hindered polyoxyalkylene polyamines. In yet another aspect, the present invention is directed to the preparation of compounds of the type mentioned above by reacting a 2,2,6,6-tetramethyl-4-piperidone with a polyoxyalkylene polyamine under Schiff base reaction conditions to form a Schiff base which is thereafter hydrogenated to form the desired ultraviolet light stabilized hindered polyoxyalkylene polyamine. In a modified form of the present invention a polyoxyalkylene polyamine is reacted with 2,2,6,6-tetramethyl-4-piperidone and hydrogenated to form the sterically hindered polyamine, which is then reacted with a hindered phenol such as 2,6-ditertiarybutylphenol and formaldehyde under Mannich condensate reaction conditions to form a Mannich derivative containing a sterically hindering oxidation inhibiting group. The products of the present invention can be utilized as ultraviolet light stabilizers for a wide variety of commercial products such as water base paints, oil base paints, polyethylenes, polypropylenes, polyurethanes, etc. In the modified form of the invention, the products are useful also to inhibit oxidation of such products.
By way of summary, the 2,2,6,6-tetramethyl-4-piperidone when reacted with the polyoxyalkylene polyamine under Schiff base reaction conditions will provide a product which, when hydrogenated will have the formula: ##STR4## wherein:
R represents an alkylene, alkyl, aralkyl, alkaryl, or aryl group containing 1 to 24 carbon atoms,
R' represents hydrogen, methyl or ethyl,
n represents a number having an average value of 1 to 70, and
x represents an integer having a value of 1 to 3.
In accordance with the modified form of the present invention wherein the product of formula I is reacted with a hindered phenol and formaldehyde under Mannich condensate reaction conditions, the Mannich derivate may be represented by the formula: ##STR5## wherein: the letters and subscripts of formula (II) have the same meaning as the letters and subscripts of formula (I), except that x equals 1 or 2 and R" represents an alkylene group or: ##STR6##
2. Prior Art
It is known to use hindered compounds such as 2,2,6,6-tetramethyl-4-piperidone and derivatives thereof as ultraviolet light stabilizers. See, for example the review entitled "Sterically Hindered Amines and Nitroxyls as Polymer Stabilizers, " Dagonneau, Ivanov, Rozantsev, Sholle and Kagan (Lab. Rech. Macromol., Univ. Paris-Nord, 93430 Villetaneuse, Fr.) J. Macromol. Sci. Rev. Macromol. Chem. Phys., 1982, C22(2), 169-202 (Eng.).
European patent application No. 0070386 for Loffeiman filed Aug. 6, 1982 discloses the preparation and use of piperidinyl analogs as ultraviolet light stabilizers. Similarly, dimeric piperidinyl derivative dimers are shown for use as light stabilizers in an article entitled "Light Stabilization of Polyurethanes", K. Berger, Kunstat. Fortschrittake 1980, 7, 80-94.
In the United States, U.S. Pat. No. 4,369,275 for Rody discloses Malonate derivatives of sterically hindered piperidinyl compounds as ultraviolet light stabilizers.
Molt U.S. Pat. No. 4,366,277 discloses compounds having 2-bis(2,2,6,6-tetramethyl-4-piperidyl) substituted heterocyclic rings and polymers containing the same which are shown to be useful as ultraviolet light stabilizers. Other U.S. patents of this gender include Tanaka et al. U.S. Pat. No. 4,386,127, Olson et al. U.S. Pat. No. 4,382,109 and Randall et al. U.S. Pat. No. 4,014,887.